Industries that use and sell large quantities of bulk, particulate, flowable compositions such as animal food, bulk foods, coffee, fertilizer, detergent and the like are often faced with the task of packaging and shipping such compositions in containers suitable for shipping, handling, retail sale, and consumer transport and use. For compositions such as bulk animal foods, such containers are typically paper or plastic bags containing up to about 75 pounds of food composition. Such containers therefore, must be able to withstand shipping and handling without breaking open.
Bags for containing and handling bulk compositions are made from various materials and secured closed in various ways depending on the properties of the bag materials, the properties of the closure systems, and cost considerations. Materials used for such bags include burlap, paper, multi-layer, and plastics including nylon, and woven polypropylene. Closure for one-time use can be accomplished by stitching, taping, gluing, heat sealing, and/or ultra sonic welding the containers closed after the containers are filled with the composition. The cost to produce such bags and closures varies with the type of bag material and type of closure used. In the retail pet food industry such bags have typically been made from multiple layers of paper, plastic, and/or foil, and stitched, taped, heat sealed and/or ultrasonically welded closed.
The materials and closures of such bags are typically selected to provide the most cost-effective container, considering material cost, material properties, closure cost, closure properties, damage and lost product due to bag breakage, etc. Bags for containing quantities of 15 or more pounds of dry pet food composition are typically multiple layered paper bags, often lined with plastic or foil on an interior surface thereof, that are stitched, taped and/or glued closed.
However, paper bags do not keep the food compositions contained therein particularly fresh over time. Oxygen, moisture, and even perhaps organisms can enter the bags. Thus, in time, the food may oxidize, become stale, become infested, and generally become less palatable to the animal and less desirable by the animal owner. Additionally, bags that are stitched, taped and/or glued closed can not be resealed once opened. Therefore, many animal owners resort to emptying the contents of the paper bag into a storage container that can be easily accessed, easily reclosed, and that keeps the food fresh.
Furthermore, such feed bags are typically rectangularly shaped with very small depth versus height of such bags. Thus, the bags must be stacked and displayed laying flat on one of the largest surfaces, usually the front or back surface. Such orientation, particularly for bags containing 15 or more pounds of composition, makes the bags difficult to display, and to remove and lift. If such bags are successfully removed from a store shelf, they are often deposited on a narrow bottom surface of the bag, and often fall over. The instability of the bags can be bothersome if one must keep righting the bag. In addition, if the bag has been taken home and opened, extensive spillage can result when the bag tips over.
Recently, manufacturers have attempted to provide bags that are reclosable and that provide enhanced spoilage protection for the contents over time, such that a user does not have to empty a large, heavy bag into a separate container. Therefore, manufacturers have begun to supply plastic bags, or paper bags with plastic or foil linings, and having reclosable features. Plastic, and plastic or foil lined materials are better moisture and air/oxygen barriers than for example, paper or burlap, and provide better protection from spoilage and infestation.
However, it has been found that many such plastic bags burst open, when filled with about 15 or more pounds of bulk composition, and dropped off of a truck, a store shelf, out of a user's vehicle or grip, or when tipped over. The bursting problem is often exacerbated when such bags are formed with a reclosable feature. Such bags can burst at the site of the reclosable feature or at one or more seals or seams of the bag, or the material forming the bag itself can tear and cause the bag to burst open. In addition, plastic bags can be slippery to the touch, and can result in a greater amount of bags dropped versus other materials such as paper, nylon or burlap.
Some manufactures have attempted to solve the problem of bags bursting at a reclosable feature by placing and sealing a material over or across the reclosable feature, which the consumer then removes once the bag is safely at its final destination. Such an approach is feasible with various paper bags, and quantities of composition over about 15 pounds in weight. However, many plastic bags still burst when they contain over about 15 pounds of material and fall from a height of about 3 feet, whether or not the bags contain a reclosable feature. Thus, the majority of bags used for containing greater than about 15 pounds of dry pet food are various types of paper bags. Other approaches include sealing the inside of the bag in addition to having a recloseable feature. Using a double thickness in the reclosable feature is another option. However, cost can increase prohibitively as more components are added to the bag.
Therefore, there is a need for a plastic bag that can contain amounts of heavy compositions and can withstand a drop from various heights without bursting open. There is also a need for such a bag to be reclosable. There is a need for such a bag to also provide moisture and oxidation barrier protection for the contents. There is also a need for the bag to be stable when situated upright on a bottom surface of the bag, and for the bag to be easily grippable.